You Didn't Lose Fitness, You Lost Fuel

If you grew up in the ‘80s and ‘90s, you were handed two contradictory rulebooks. First, fat was the enemy. Then, almost overnight, fat was fine and carbohydrate was the problem. Neither was built on good science, and neither was built with active women in mind, yet both stuck.

I see the impact everywhere: women who are highly active, lift heavy, know what they’re doing—and still hesitate when it comes to eating a slice of toast. Too many women have quietly reduced their carbohydrate intake over the years without ever consciously deciding to. And it’s not a discipline problem; it's decades of accumulated messaging doing exactly what it was designed to do.

Scarcity Is A Signal

Low carbohydrate availability sets off a signaling cascade, triggered by your body detecting scarcity and responding accordingly: cortisol rises, sex hormone production drops, and LH (luteinizing hormone) pulsatility gets disrupted (the hormonal signal that drives ovulation arrives in a rhythm, and under scarcity that rhythm gets ragged). 

You don't need a clinical RED-S (Relative Energy Deficiency in Sport) diagnosis for this to be happening. RED-S is the severe end of a long spectrum, and you can sit well short of it and still pay—in adaptation, recovery, bone, mood, and cycle regularity. Carbohydrate restriction is one of the fastest routes into low energy availability. 

Here's the Part I Want You to Hear

Most of what I ask women to change takes months to show up. This one doesn't.

Muscle glycogen replenishes in roughly 24 to 48 hours once you're eating enough. In my experience, women notice within three to four days—not in a blood panel, but in their workouts. Your warm-up stops feeling like work. The intervals you've been dreading feel good. I've had women come back after a single week convinced I'd changed their program, yet I hadn't touched it. They were simply fueling adequately for it.

You don't have to commit to a philosophy or take my word for the hormonal case. Eat enough carbohydrate for four days and pay attention to how your training feels. The evidence arrives fast enough that you can evaluate it for yourself.

So How Much Is Enough?

More than you're eating now. That's true for almost every active woman who comes to me.

One caveat before the numbers: the carbohydrate guidelines we have were built largely on male athletes. There isn't a female-specific version, because that research hasn't been done yet. So treat what follows as a starting point to test against how you feel and train, not a prescription.

As a working range, aim for 3 to 5 grams of carbohydrate per kilogram of body weight on easier training days, rising to 5 to 7 g/kg when you're going longer or harder. In imperial, that's 1.4 to 2.3 grams per pound, rising to 2.3 to 3.2.

For a woman who weighs 150 lb (68 kg), that's roughly 210 to 345 grams on easier days and 345 to 480 grams on harder ones. Most women I work with are starting below the bottom of that range and don't realize it.

Remember that you don't need to hit the same number every day. Carbohydrate intake should track your training load: more on the days that ask for it, less on the days that don't.

The Window That Doesn't Change

It's (hopefully) not news that you need to take on carbs plus protein within about 60 minutes of finishing a workout. But this is not just about the anabolic window as it's usually sold, it's also about signaling. Post-exercise is when cortisol is highest and your body is assessing the breakdown that occurred during exercise and how to best repair it. Food arriving then is the clearest possible answer: that stress is finished, it’s time to start the building and repairing process, it's worth adapting to this.

This holds true at every life stage, but what shifts is the context around it:

• Still cycling: the luteal phase modestly raises resting energy demand (some studies report by up to 5–10%). Rising progesterone reduces insulin sensitivity and shifts the body toward burning relatively more fat and less carbohydrate—patterns that argue against cutting calories or carbs hard in the back half of your cycle (which is precisely when many women cut back).

• Perimenopause: the shifting estrogen-to-progesterone ratio brings anabolic resistance and reduced insulin sensitivity, which gets misread as an instruction to cut carbs. It isn't. Concentrate carbohydrates around training rather than reducing your overall intake, and anchor to your training rather than your cycle, which has likely stopped being predictable.

• Postmenopause: your activity level sets the requirement, not your menstrual status. The hormonal context changed but the fuel demand didn't.

Where to Start

• Focus on the post-exercise meal first: 30 grams of protein reasonably soon after finishing exercise (ideally within an hour)—closer to 40 grams if you're perimenopausal or beyond—paired with carbs (at least 1.2 g/kg following prolonged exercise). Be consistent for a week before you change anything else.
• Always fuel the work itself—before, during (for sessions over 90 minutes), and after. Harder days mean more carbohydrate, not the same amount every day.
• Judge week one by how training feels: your warm-ups, your intervals, your RPE.
• Judge the next few months by your cycle, your sleep, and your energy between sessions. Cortisol, thyroid conversion, and cycle restoration can take three to six months depending on how deep the deficit ran.
• Expect the scale to move up: Glycogen binds water as it’s stored so it's not uncommon to see your weight rise. That’s good news: it's physical evidence your muscles are storing fuel again.
• Some of my go-to carbs include toast (yes, really—and I consider it a big win when women I work with start eating toast!) and overnight oats. And here’s what I consider an ideal breakfast for busy women.

Remember: carbohydrate isn't a caloric indulgence you earn with a hard enough effort. Women perform best fueled. That shouldn't be radical. The messaging is what needs undoing—not your carb intake.

Give it four days.

Find What’s Relevant to You, Faster! 

You shouldn't have to hunt for the information that applies to you, so I’m excited to share that my new website is live today. It has been redesigned around how you actually use it with everything clearly organized by life stage. Whether you're coaching active teenage girls, training through perimenopause, or figuring out what post-menopause means for your fueling and recovery, you can get to what's relevant to you in seconds. Take a look around the new site.

Why Women Need Carbs

In this short clip you can learn more about how to use different types of carbs, as well as the importance of pairing them with protein, to help stabilize blood sugar, protect hormonal health, and improve recovery.

Low Energy Availability in Women: Why Post-Workout Fueling Is Crucial

When you fuel after training isn't a minor detail—for women, delaying it sends a stress signal that can impact our hormones, recovery, and bone health. Here's what low energy availability actually does, and how to stay ahead of it.

Until next time, 

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